leaky tank

[etet]

I just bought an '81 gs850g on ebay and have not had the chance to check it out too much, fo far I am impressed. The seller told me the petcock leaked. It does a little but the real leak is from the right side of the tank (underneath). I did not see this when I checked the bike out when picking it up. There has been some previous repair - looks like fiberglass. It is leaking and seems dangerous to me. I will not ride it until it is fixed. My question is in looking for a replacement tank if it can't be fixed, which years and models of GS bikes have a tank that will fit this bike. It looks like it has a single bolt at the back of the tank at the seat. Also any ideas on a good fix for this tank is appreciated. I haven't got it off of the bike yet, just thought I would go ahead and ask.
Thanks - et

[bwringer]

If it's a G model, the tanks from 1979-81 GS850G and GS1000G will fit.

If it's a GL model, you'll need an 1980-81 850GL or 1000GL tank.

I'm pretty sure that tanks from chain drive models will not fit -- you'll need a tank from a shaftie of the same body style (G or GL).

There's a good chance a decent radiator repair shop can salvage the tank, too. In some cases, the process will likely destroy the paint, but you'll have to drain it and bring it in to see what they can do. They might braze a leak and then chemically seal the inside.

Another thought is that it might simply be leaking from the gasket surrounding the fuel level sender, which is on the right side. Look closely to make sure you know where the gas is coming from.

[etet]

tank now off

the tank has some type of tape repair on one inside edge. this is where the leak is coming from. is there some type of epoxy repair available?
Thanks

[tfb]

Epoxy repair kits are indeed available.

I have used one called 'QuikSteel' (available here in Australia; not sure about where you are); it's just a strip of epoxy putty with some hardener running up the middle. You just cut off a slice of the amount you require, then knead it to work the hardener through the putty, then push it on to the leaking spot (which you have preferably cleaned back to bare metal with a piece of sandpaper). It goes rock-hard within 5 minutes.

Then you can chemically treat the inside of the tank, and line it with Kreem or POR-15 or some other kit like that. Most folks on the forum here will recommend you avoid the Kreem though.